Design and application of rock blasting teaching experimental platform based on metal wire electric explosion

The drilling and blasting method is a widely used technique in tunnel excavation and mining engineering. However, chemical blasting tests pose significant risks and are difficult to control. Owing to strict regulations, the use of explosives in universities is heavily restricted, leaving most universities in China without the ability to use chemical explosives to conduct mining blasting tests or offer related blasting teaching and experimental platforms. To address this issue and facilitate indoor rock blasting experimental teaching, a metal wire pulse electric blasting platform has been designed.

The platform consists of a high-voltage pulse generation system, a trigger control system, a safety grounding system, and a non-contact ultra-dynamic strain field monitoring system. The high-voltage pulse generation system injects powerful, fast pulse currents into metal wires, causing them to transition from solid to plasma and explode electrically through Joule heating. The resulting plasma channel generates shock waves at GPa levels. By adjusting the charging voltage, the energy for rock breaking can be precisely controlled. Different geometric shapes of metal wires simulate various charge structures. Straight metal wires mimic the structure of columnar drug packaging, while metal coiled wires like mosquito coils resemble the structure of spherical drug packaging. The trigger control system minimizes strong electromagnetic interference and accurately controls the discharge time of the energy storage capacitor. The safety grounding system adopts a dual method using an oil switch and grounding rod to ensure experimental safety. The ultra-dynamic strain field non-contact monitoring system consists of a high-speed camera and a digital speckle analysis component to accurately capture the entire process of rock strain field evolution.

The platform has successfully simulated experiments with both columnar and spherical explosive charges. The results indicate that the blasting damage characteristics of rocks owing to metal wire electric explosion closely resemble those caused by chemical explosive blasting, particularly regarding the shape of the blasting funnel. By employing digital speckle analysis technology, the platform provides insights into the evolution of the free surface strain field by analyzing the cloud map of the ultra-dynamic strain field during rock blasting. The experiment shows that high-power pulse electric explosion technology can effectively simulate the rock blasting process in various blasting environments, allowing for visualization of the dynamic process of rock blasting damage.

Compared with traditional chemical blasting experiments, the rock blasting teaching experimental platform utilizing metal wire electric explosion is more flexible, safe, precise, and controllable. Key factors affecting the blasting effect, such as energy, charge shape, and the depth of the sample’s resistance line, can be artificially controlled within the platform. This adaptability meets diverse experimental needs, improving the teaching effect of rock blasting and boosting students’ scientific research and innovation skills. The platform is recommended for broader application in scientific research and teaching.